6
P loads vary from year to year but no long-term decline has occurred.

7
The difference between P input and P output is declining over time = reduced assimilation.

8
The concentration of TP in the lake has increased over time, except in recent drought years.

9
In shallow shoreline areas that support SAV, fish habitat, and most human uses, water quality and biological conditions are excellent when the lake depth is low, regardless of high P out in the deeper mid-lake region.

10
Why have the lake and watershed not responded to all the P reduction measures? Legacy phosphorus in the soils, wetlands and lake sediments – phosphorus that accumulated there over decades when there was high export from agricultural lands, and is now slowly leaching back into the surface water.

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Management implications P control measures up in the watershed will not achieve load reduction for decades or longer More immediate P reduction would require large-scale wetland treatment right at the lake Lake sedimentary P still will delay recovery Yet there is an opportunity to achieve good conditions for fish, SAV, and users in near-shore area if lake depths can be kept low, perhaps through large-scale storage of water in the basin